Specify species and parameter interactions


The Rule property contains a rule that defines how certain species and parameters should interact with one another. For example, a rule could state that the total number of species A and species B must be some value. Rule is a MATLAB® expression that defines the change in the species object quantity or a parameter object Value when the rule is evaluated.

You can add a rule to a model object with the addrule method and remove the rule with the delete method. For more information on rules, see addrule and RuleType.


Applies toObject: rule
Data typechar string
Data valueschar string defined as species or parameter objects. Default is empty.


  1. Create a model object, and then add a reaction object.

    modelObj = sbiomodel ('my_model');
    reactionObj = addreaction (modelObj, 'a + b -> c + d');
  2. Add a rule.

    ruleObj = addrule(modelObj, '10-a+b')

    MATLAB returns:

    SimBiology Rule Array
    Index:    RuleType:    Rule:
    1         algebraic    10-a+b
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